1. Field of the Invention
The present invention relates to an image shake correction apparatus and method for use in a camera. More particularly, the present invention relates to an image shake correction apparatus and method that reduces frictional loss in a camera caused by vibration or shaking.
2. Description of the Related Art
Related image shake correction apparatuses are provided in photographing apparatuses to correct for shaking images when taking a picture. The image shake correction apparatus is installed on a main body of the photographing apparatus so that an image pickup device, on which an image is focused, can be moved in two perpendicular directions in a single plane. The image shake correction apparatus detects vibrations of the photographing apparatus, and changes a position of the image pickup device according to the detected values in order to prevent shaking the image focused by the image pickup device.
Referring to FIG. 1, a related image shake correction apparatus generally includes a first image pickup device stage 90, on which an image pickup device assembly 10 including an image pickup device is mounted, a second image pickup device stage 20 coupled to the first image pickup device stage 90, and actuators 40 and 42 moving the first and second image pickup stages 90 and 20, respectively. The image shake correction apparatus is installed on a base plate 80. The first and second image pickup device stages 90 and 20 are respectively connected to shafts 94 and 24 through connection portions 92 and 22, respectively, and guided in a predetermined direction. The first and second image pickup device stages 90 and 20 move parallel to the axial directions of the shafts 94 and 24. When signals for correcting image shake are input to the actuators 40 and 42, the actuators 40 and 42 move the first and second image pickup device stages 90 and 20 in a direction of correcting the image shake.
Referring to FIG. 2, another related image shake correction apparatus includes coils 45 and 48 and magnets 44 and 46 as actuators that operate first and second image pickup device stages 90 and 20. In the image shake correction apparatus of FIG. 2, the coils 45 and 48 are electrically connected with each other so that the first and second image pickup device stages 90 and 20 are driven by electromagnetic force generated with respect to the magnets 44 and 46. Thus, when power is turned off, the first and second image pickup device stages 90 and 20 move freely. In order to prevent the first and second image pickup device stages 90 and 20 from moving freely, the first and second image pickup device stages 90 and 20 require locking tools. A related device prevents an image pickup device stage from moving perpendicularly to a driving direction of an actuator by installing an insertion portion on an engaging portion of the actuator and the image pickup device stage. In addition, another related device provides an actuator that includes a voice coil actuator and a coil portion includes a yaw coil and a pitch coil.
Meanwhile, in the related image shake correction apparatus shown in FIG. 1, the shafts 24 and 94 guiding the image pickup device stages 20 and 90 are disposed on outer portions of the image pickup device stages 20 and 90. However, centers of the image pickup device stages 20 and 90 and center axes of the shafts 24 and 94 are separated from each other by distances ΔX and ΔY, and thus, when the image pickup device stages 20 and 90 move, torques occur because the image pickup device stages 20 and 90 rotate with respect to the center axes of the shafts 24 and 94. The torques become larger when the distances ΔX and ΔY become longer.
Therefore, the torques generated due to the rotations of the image pickup device stages 20 and 90 act against the motion of the actuators 42 and 40 that move the image pickup device stages 20 and 90. In addition, a friction loss may occur when the image shake correction apparatus is driven, or the image pickup device may vibrate. Also, the shafts 24 and 94 guiding the image pickup device stages 20 and 90 are axial members having lengths in a predetermined direction, and thus, the shafts 24 and 94 must be disposed on the outer portions of the image pickup stages 20 and 90. Accordingly, the shafts 24 and 94 guiding the image pickup device stages 20 and 90 are still separated from the centers of the image pickup device stages 20 and 90.